U.S. patent number 5,665,098 [Application Number 08/685,393] was granted by the patent office on 1997-09-09 for unitary removal of plaque.
This patent grant is currently assigned to EndoVascular Instruments, Inc.. Invention is credited to Thomas L. Kelly, Thomas A. Wiita.
United States Patent |
5,665,098 |
Kelly , et al. |
September 9, 1997 |
Unitary removal of plaque
Abstract
Novel apparatus and related methods are disclosed by which
plaque is connected to the head of a removal instrument for removal
of a unitary segment of plaque from an artery intact to increase
blood flow through the artery.
Inventors: |
Kelly; Thomas L. (West Linn,
OR), Wiita; Thomas A. (Lake Oswego, OR) |
Assignee: |
EndoVascular Instruments, Inc.
(Vancouver, WA)
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Family
ID: |
23869117 |
Appl.
No.: |
08/685,393 |
Filed: |
July 23, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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470805 |
Jun 6, 1995 |
5571122 |
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973514 |
Nov 9, 1992 |
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Current U.S.
Class: |
606/159; 604/22;
606/170; 606/180 |
Current CPC
Class: |
A61B
17/32075 (20130101); A61B 17/320758 (20130101); A61B
17/320783 (20130101); A61B 2017/00473 (20130101); A61B
2017/00685 (20130101); A61B 2017/22038 (20130101); A61B
2017/22094 (20130101); A61B 2017/320008 (20130101); A61B
2017/320044 (20130101); A61M 25/104 (20130101) |
Current International
Class: |
A61B
17/22 (20060101); A61B 17/32 (20060101); A61B
17/00 (20060101); A61M 29/02 (20060101); A61B
017/32 () |
Field of
Search: |
;606/1,108,159,170,171,180 ;128/751-755,899 ;604/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0177519 |
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Nov 1977 |
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EP |
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9230161 |
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Sep 1992 |
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EP |
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3532653 |
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Dec 1961 |
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DE |
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8200283 |
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Jun 1990 |
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SE |
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197712 |
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Dec 1977 |
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SU |
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7646849 |
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Sep 1980 |
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SU |
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9201054 |
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Feb 1992 |
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WO |
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9202222 |
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Mar 1992 |
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WO |
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Other References
Reprint from Surgery St. Louis, vol. 57, No. 1, pp. 22-27, Jan.
1965. .
American Edwards Laboratories description sheet for Fogarty
Arterial Emboloectomy Catheters, publication date unknown..
|
Primary Examiner: Lewis; William
Attorney, Agent or Firm: Foster & Foster
Parent Case Text
This application is a continuation of U.S. patent application Ser.
No. 08/470,805, filed Jun. 6, 1995, now U.S. Pat. No. 5,571,122,
which is a continuation-in-part of U.S. patent application Ser. No.
07/973,514, filed Nov. 9, 1992, now abandoned.
Claims
What is claimed and desired to be secured by Letters Patent is:
1. A method of excising material comprising plaque from an artery
comprising the steps of:
inserting an instrument into the artery, the artery having an
axis;
placing the instrument adjacent to the material comprising plaque
in the artery;
grasping the material comprising plaque with the instrument without
materially cutting the material comprising plaque by the
instrument;
maintaining the grasp of material comprising plaque while
displacing the instrument thereby generally axially separating a
length of the material comprising plaque from other material in the
artery;
removing the dislodged length of material comprising plaque from
the artery.
2. A method of removing material comprising arterial plaque
comprising the steps of:
grabbing hold of the material comprising plaque within an artery
with a removal instrument;
applying force to the material comprising plaque generally along
the length of the artery to part a segment of said material from
other wall material in the artery without longitudinally cutting
the segment;
withdrawing the segment of material comprising plaque from the
artery.
3. A method of increasing blood flow in an artery comprising the
steps of:
introducing a gripping instrument into an artery through a man-made
opening therein;
displacing the gripping instrument along the artery to a site where
the artery is obstructed at least in part by material comprising
plaque;
gripping the material comprising plaque at the site with the
gripping instrument;
tearing at least some the material comprising plaque from the
artery without appreciably cutting the material comprising plaque
along the axis of the artery by displacing the instrument while the
instrument is gripping the material comprising plaque;
removing the instrument and the gripped material comprising plaque
through the manmade opening.
4. A method of increasing blood flow in an artery comprising the
steps of:
tethering arterial material comprising plaque to an indwelling
instrument at a site within the artery with immaterial axial
cutting of tethered material comprising plaque, pulling the
instrument and the material comprising plaque along the length of
the artery thereby forcibly tearing a segment of the material
comprising plaque, in the direction of the length of the artery,
from a portion of the artery and removing the torn segment of the
material comprising plaque from the artery.
5. A method of treating material comprising plaque in an artery
having an elongated length to increase blood flow comprising the
steps of:
inserting a connecting head into an artery;
locating the head adjacent to material comprising plaque within the
artery;
removably connecting the head to the material comprising plaque
without cutting the material comprising plaque from the artery
along its length;
pulling on the material comprising plaque through the head thereby
parting a segment of the material comprising plaque intact from the
artery;
retrieving the head and connected severed segment of the material
comprising plaque from the artery.
6. A method according to claim 5 wherein the inserting step is
preceded by creating at least one man-made opening in the
artery.
7. A method according to claim 6 wherein the inserting step
comprises placing a guidewire through the opening and advancing the
head into the artery along the guidewire.
8. A method according to claim 5 wherein the inserting step is
preceded by preliminarily loosening the material comprising
plaque.
9. A method according to claim 8 wherein the loosening step
comprises making at least one primarily radial cut in the material
comprising plaque.
10. A method according to claim 5 wherein the locating step
comprises placing the head within a central lumen of the
artery.
11. A method according to claim 5 wherein the removably connecting
step comprises taking hold of the material comprising plaque by the
head.
12. A method according to claim 5 wherein the removably connecting
step comprises grasping the material comprising plaque by the
head.
13. A method according to claim 5 wherein the removably connecting
step comprises grasping the material comprising plaque by the
head.
14. A method according to claim 5 wherein the removably connecting
step comprises engaging the material comprising plaque by the
head.
15. A method according to claim 5 wherein the severing step
comprises shearing the material comprising plaque intact from a
wall of the artery.
16. A method according to claim 5 wherein the retrieving step
comprises removing the head and the severed segment of material
comprising plaque from the artery.
17. A method according to claim 5 wherein the removably connecting
step comprises hooking the material comprising plaque with the
head.
18. A method according to claim 5 wherein the removably connecting
step comprises piercing the material comprising plaque with the
head.
19. A method according to claim 5 wherein the removably connecting
step occurs due to rotating the head.
20. A method according to claim 19 wherein the rotating step
comprises causing the head to bindingly bite into the material
comprising plaque.
21. A method according to claim 19 wherein the rotating step
comprises embedding material comprising plaque within the head in
binding relation.
22. A method according to claim 5 wherein the removably connecting
step comprises binding the material comprising plaque and the head
together.
23. A method according to claim 5 wherein the removably connecting
step comprises snagging the material comprising plaque with the
head.
24. A method according to claim 5 wherein the locating step
comprises advancing the head to an arterial location remote from
the insertion site.
25. A method of treating material comprising arterial plaque in an
artery to increase blood flow comprising the steps of:
preliminarily loosening the material comprising arterial plaque by
subjecting the material comprising arterial plaque to be removed to
dottering;
inserting a connecting head into an artery;
locating the head adjacent to the preliminarily loosened material
comprising arterial plaque within the artery;
removably connecting the head to the material comprising arterial
plaque;
pulling on the material comprising arterial plaque through the head
thereby part severing a segment of the material comprising arterial
plaque intact from other material remaining in the artery;
retrieving the head and the connected severed segment of the
material comprising arterial plaque from the other material
remaining in the artery.
26. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
preliminarily displacing the material comprising plaque by
subjecting the plaque to be removed to balloon angioplasty;
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising
plaque;
pulling on the material comprising plaque through the head thereby
severing a segment of the material comprising plaque intact from a
remainder of material in the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the remainder of material in the
artery.
27. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery by placing the head within the artery between the
material comprising plaque and a wall portion of the artery so that
insertion of the head separates at least in part the material
comprising plaque and the artery at the interface between the
two;
removably connecting the head to the material comprising
plaque;
pulling on the material comprising plaque through the head thereby
dividing a segment of the material comprising plaque intact from a
remaining wall portion of the artery;
retrieving the head and the connected divided segment of the
material comprising plaque from the wall portion of the artery.
28. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising the plaque
by compressively engaging and holding the material comprising
plaque at the head;
pulling on the material comprising plaque through the head thereby
parting a segment of the material comprising plaque intact from
material remaining in the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the material remaining in the
artery.
29. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising
plaque;
pulling on the material comprising plaque through the head by
stretching the material comprising plaque thereby separating a
segment of the material comprising plaque intact from other
material remaining in the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the other material remaining in the
artery.
30. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising
plaque;
pulling on the material comprising plaque through the head thereby
causing a segment of the material comprising plaque to peel intact
from other material remaining in the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the other material remaining in the
artery.
31. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising
plaque;
pulling on the material comprising plaque through the head thereby
removing a segment of the material comprising plaque intact from
the other material remaining in the artery by both axially
separating the segment from the other material remaining within the
artery and displacing the segment in respect to the other material
remaining in the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the other material remaining in the
artery.
32. A method of treating material comprising plaque in an artery to
increase blood flow comprising the steps of:
inserting a connecting head into an artery;
locating the head adjacent to the material comprising plaque within
the artery;
removably connecting the head to the material comprising plaque by
clamping the head to the material comprising plaque;
pulling on the material comprising plaque through the head thereby
severing a segment of the material comprising plaque intact from
the remainder of the artery;
retrieving the head and the connected severed segment of the
material comprising plaque from the remainder of the artery.
Description
FIELD OF INVENTION
The present invention relates generally to increasing blood flow in
arteries and, more particularly, to unitary removal of a segment of
plaque from an artery.
BACKGROUND
Constricted blood flow in human arteries due to build-up of plaque
is a common ailment and creates serious risks to the quality of
life and, in some cases, e.g. , when build-up occurs in coronary
arteries, to life itself, too frequently at an early age.
Past efforts to address the problem of plaque accumulation in
arteries have consisted primarily of conventional endarterectomy,
by-pass surgery, dilation of the afflicted arteries using dottering
or balloon angioplasty (PTA and PTCA), atherectomy, and successive
severing of thin layers of plaque by reason of repeated passes of a
cutting or grinding instrument along the plaque region where
removal is desired. The plaque-cutting technique also requires that
debris, in the form of plaque fragments released into the blood
stream, be collected and removed from the artery to avoid
complications (such as embolization and thrombosis). Laser removal
of plaque is also known.
Conventional endarterectomy is invasive. By-pass surgery is
traumatic to the tissue, very expensive, very invasive, and creates
the greatest risk to the patient. Balloon angioplasty and/or
dottering are often only a temporary or short-term solution, as all
of the plaque in the afflicted artery at the time of treatment
remains there. Dilation only rearranges plaque and may cause pieces
of plaque to break loose into the blood stream. Additional build-up
of plaque at the site of treatment can be prevented or alleviated
by exercise and diet control, if patient compliance can be
achieved. Atherectomy has demonstrated poor long-term results, at
least in peripheral vessels.
Repeated cutting of the atheroma using a reciprocated instrument
offers promise, but cannot be performed rapidly, may not remove all
of the plaque at the treatment site, and risks complications when
and if plaque fragments are not collected and thus escape to flow
with blood to other parts of the cardiovascular system. Laser
removal of plaque has also shown poor long-term results in some
studies.
All present treatments exhibit restenosis, a complex, poorly
understood process by which the artery becomes re-blocked by
material that includes uncontrolled growth of smooth muscle cells
(intimal hyperplasia or myointimal fibroplasia). All present
treatments vary in perioperative measures of desirability,
including duration of procedure, degree of invasiveness of
procedure, number and size/length of surgical incisions required,
length of stay in hospital, recuperation/healing time, time until
return to work, degree of anesthesia (local/general) required,
overall procedure risk, and overall treatment cost.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
In brief summary, the present invention overcomes or alleviates
problems of the prior art. It is believed that a less traumatic,
lower risk, less expensive, less invasive, less time-consuming, and
more efficacious plaque treatment apparatus and related methods are
provided by which a unitary segment of plaque is removed intact
from an artery.
With the foregoing in mind, it is a primary object to overcome or
alleviate problems of the prior art.
A further object of paramount importance is the provision of novel
plaque treatment apparatus and related methods.
Another object of value is the provision of apparatus and
methodology by which a unitary segment of plaque is removed intact
from an artery.
An additional object of importance is the provision of what is
believed to be a significantly less traumatic, lower risk, less
expensive, less invasive, less time-consuming, and more efficacious
way of treating plaque.
A further object of significance is the provision of a novel plaque
removal apparatus and method having one or more of the following
features: (1) applicable for plaque removal in arteries of all
sizes including all peripheral, coronary, and carotid arteries, (2)
which can use one or two relatively small incisions, (3) which is
effective with or without pre-loosening of plaque; (4) which is
operable with or without a guidewire; (5) which can be placed in
the artery of choice either concentrically or eccentrically; (6)
usable alone or in combination without other plaque treating
procedures; (7) usable in both partially and totally occluded
arteries; and (8) useable in either an open surgical procedure or a
percutaneous procedure.
These and other objects and features of the present invention will
be apparent from the detailed description taken with reference to
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary longitudinal cross-section of a
plaque-connecting instrument, in diametrally-constricted
orientation, disposed in a plaque-ladened artery.
FIG. 2 is a fragmentary longitudinal cross-section illustrating the
instrument being pulled while in a radially-expanded,
plaque-connecting position;
FIG. 3 is a transverse cross-section taken along lines 3--3 of FIG.
2;
FIG. 4 is a fragmentary longitudinal cross-section of a second
plaque-connecting instrument, in a diametrally-constricted
orientation, disposed in a plaque-ladened artery.
FIG. 5 is a fragmentary longitudinal cross-section illustrating the
instrument being pulled while in a radially-expanded
plaque-connecting position;
FIG. 6 is a transverse cross-section taken along lines 6--6 of FIG.
5;
FIG. 7 is a fragmentary longitudinal cross-section of a
plaque-connecting instrument, being pulled while in a hooked
position with plaque in an artery;
FIG. 8 is a fragmentary longitudinal cross-section similar to FIG.
7 showing a segment of plaque being displaced with the connecting
instrument along the length of the artery;
FIG. 9 is a transverse cross-section taken along lines 9--9 of FIG.
8;
FIG. 10 is an elevational view of a segment of plaque removed
intact from an artery using the present invention;
FIG. 11 is a flow chart depicting various ways of implementing the
present invention; and
FIG. 12 is a fragmentary longitudinal cross-section of the
plaque-connecting instrument eccentrically or asymmetrically
inserted into an artery, i.e., between the inner arterial wall and
the plaque.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Reference is now made to the drawings wherein like numerals are
used to designate like parts throughout. The present invention
provides for unitary, intact removal of a segment of plaque from an
artery to resolve or alleviate constrictive blood flow problems in
human arteries. The invention overcomes or alleviates health risks
associated with conventional endarterectomy, by-pass surgery,
dottering and balloon angioplasty procedures, atherectomy,
reciprocal cutting of layers of plaque, and laser plaque removal.
It is believed that intact removal of one or more segments of
plaque, in accordance with the principles of the present invention,
is less traumatic, creates lower risks, is less expensive, is less
invasive, less time-consuming, and is more efficacious than by-pass
surgery, angioplasty, and reciprocal cutting of plaque.
Reference is now made to FIG. 11, for the purpose of providing a
description of the present invention which is comprehensive.
Initially, at least one man-made opening and in some cases only one
opening is created in the artery, at a readily accessible site, for
which plaque treatment is desired. This can be done conventionally,
by making a small surgical incision in the artery of no greater
size than needed or by making a small puncture in the vessel, such
as a percutaneous puncture, followed by conventional insertion of a
guidewire, which may or may not be followed by sheath insertion
including insertion of a sheath particularly suitable to plaque
removal.
As a preliminary to intact removal of a unitary segment of plaque,
one or more plaque-loosening techniques may be employed, at the
discretion of the health care provider. For example, where one
incision or other man-made opening is used, the plaque adjacent
thereto may be generally radially and/or circumferentially cut or
bluntly dissected so as to make removal easier, sure, and
predictable. Where two incisions or other man-made openings are
made in the length of artery to be treated, the plaque, at both
man-made openings, may be generally radially and/or
circumferentially cut or bluntly dissected for ease and
predictability of plaque segment removal.
If desired, a dottering instrument may be inserted and caused to
vibrate and/or rotate so as to impact in a sequential fashion upon
plaque adhering to the interior wall surface of the length of
artery to be treated. The dottering instruments disclosed in
pending U.S. Trademark application Ser. No. 07/943,514, filed Nov.
9, 1992 now abandoned (owned by the assignee of the present
invention), may be utilized to so preliminarily loosen the plaque
to be later unitarily removed from the artery. A second purpose for
use of a dottering instrument is to enlarge the lumen or pathway to
permit insertion of the plaque-connecting instrument.
Thereafter, a suitable instrument is placed, inserted, or
introduced through the man-made opening into the artery, for
example, although not necessarily, along an indwelling guidewire.
The insertion can be generally concentric within the plaque-ridden
tureen of the artery (see FIG. 1, for example) or eccentric, i.e.,
between the arterial wall and the plaque (see FIG. 12, for
example).
After instrument insertion, instrument displacement continues, by
exercise of external control, until the head of the instrument has
been displaced to and located at a desired site adjacent to plaque
within the artery, normally removed or remote from the insertion
site. A suitable external control, which may be used in practicing
the principles of the present invention, is disclosed in co-pending
U.S. patent application Ser. No. 07/973,514, filed Nov. 9, 1992
(owned by the assignee of the present invention).
When so disposed, positioned, or placed, the head of the instrument
is connected, on a temporary or releasible basis, to the adjacent
plaque whereby the instrument is tethered to the plaque. The
connection may be by grabbing, gripping, compressively holding,
clamping, and/or embedding plaque within the head so as to bind
together the plaque and the head, grasping, and/or holding the
plaque by or at the head. The connection may or may not also
simultaneously create a tapering interface between the engaged
plaque and neighboring plaque that has not been engaged.
Once the releasible connection has been created between the head of
the instrument and the adjacent plaque, the instrument is displaced
so as to apply force to the tethered plaque, i.e., the plaque to
which the releasible connection has been made. While the primarily
force is one of pulling or stretching the plaque along the length
of the artery in a direction generally parallel to the longitudinal
axis of the artery and opposite to the direction of insertion,
other motions may also be used. For example, the releasible
connection internally within the artery may be achieved using at
least some rotation and, thereafter, additional rotation may be
applied in one or both directions to assist in separating a length
of plaque from its adhered relation within the artery. Similarly,
the head may be advanced and retracted to the same end. In some
applications including two-incision situations, the plaque may be
engaged and then pushed toward the second incision, rather than
being pulled back toward the first incision. The direction of the
insertion and force applied is independent of the arterial flow
direction, i.e., it may be either antegrade or retrograde to normal
blood flow.
The above-mentioned instrument displacement while the head is
releasibly connected to the plaque results in tearing, severing,
shearing, separating, and/or peeling instantly or progressively of
a segment of plaque as a unit from the artery. The plaque segment
can be separated from residual arterial plaque, including adjacent
plaque by tearing or shearing or by radially and/or
circumferentially curing using a suitable instrument. Plaque may
also separate along a created tapering interface due to the force
transmitted through the connecting plaque as it is manipulated by
the connecting instrument.
One principle at work here is that a chain is as strong as its
weakest link. The force transmitted to the plaque eventually
produces separation at the plane between tissue layers where the
connection between the layers is weakest. In practice, this weakest
connection generally occurs at the plane between the diseased
tissue and the non-diseased tissue. The weakness at this plane is
related to the weakness exploited using blunt dissection in
conventional endarterectomy, although the physical mechanism
described herein exploits this weakness in quite a different way
which in no way employs the blunt dissection used in conventional
endarterectomy.
The severed unitary segment of plaque is, finally, retrieved,
withdrawn, and removed from the artery through the insertion site
along with the instrument head to which the plaque segment is
temporarily connected, or through another site toward which the
head has pulled or pushed the plaque.
While the health care provider can, thereafter, insert a synthetic
or biologically-obtained lining into the treated artery, the
present invention comprehends as well terminating the procedure
upon withdrawal of the plaque segment and removal head, followed by
suitable closing of the one or more man-made openings in the
artery.
The present invention comprehends provision of an apparatus for
excising a segment of plaque intact from the artery which comprises
an instrument equipped with a plaque-engaging head comprising a
connector by which the head is temporarily joined to plaque within
the artery and by which force is applied to the plaque to loosen
and remove a continuous segment thereof. The instrument comprises a
mechanism including an external control by which the instrument,
its head, including its connector, are manipulated to locate the
head adjacent the plaque to be engaged, which is normally remote
from the insertion site, for temporarily or releasibly connecting
the connector to the plaque without severing or fragmenting the
plaque, for applying a force across the connector to the connected
plaque sufficient to sever the segment of plaque intact from the
artery and for removing the severed segment of plaque from the
artery. A typical length of plaque so removed from an artery is
illustrated in FIG. 10. The plaque segment can be short or it can
be very long, for example 15-18 inches. It is, however, to be
appreciated that the present invention is not restricted to any
particular type of instrument. Any instrument capable of being
connected to arterial plaque at a desired site and by which the
connected plaque can be unitarily removed intact as a segment from
the artery may be used. The form of releasible connection may be
binding, snagging, compressively holding, taking hold of, grasping,
grabbing, hooking, piercing, rotational engagement, clamping,
biting, embedding, or in any other suitable way.
Notwithstanding the foregoing, FIGS. 1-3, 4-6, and 7-9 illustrate
different mechanical configurations by which an instrument head is
temporarily connected to plaque for purposes of unitary removal
intact of a plaque segment. With specific reference to FIGS. 1-3,
an instrument, generally designated 20, is there illustrated as
having been inserted through a man-made opening in an artery,
generally designated 22, in a generally concentric fashion so as to
be disposed generally centrally within a lumen 24 of the artery
constricted by a surface-irregular deposit of plaque 26. Insertion
is illustrated as being achieved conventionally along an indwelling
guidewire 28 in a collapsed or diametrically-small configuration.
The instrument comprises a first relatively large tube 30 through
which a smaller tube 32 generally concentrically passes. The
instrument 20 comprises a head, generally designated 34 comprising
a plurality of plaque connectors, each designated 36, in the form
of resilient, helically-disposed blades. Each blade 36 is
illustrated as being centrally enlarged at 37. The blades are
joined at their respective proximal ends to the proximal portion 38
and to a distal tip 40 at their respective distal ends and may or
may not pivot at their ends relative to proximal portion 38 and
distal tip 40. The tube 32 extends centrally between the blades 36
and is securely non-rotatably fastened to the proximal portion of
the distal tip 40.
Once the head 34, in its constricted position, is disposed at a
desired location along the artery 22 adjacent a desired portion of
plaque 26, an exterior control, such as the one disclosed in
pending U.S. patent application Ser. No 07/973,514, filed Nov. 9,
1992, is used to longitudinally retract tube 32 and tip 40 in
respect to tube 30 causing the plaque-connector blades 36 to flex
from the constricted position of FIG. 1 to the radially expanded
position of FIG. 2.
Thereafter or simultaneously therewith, the head 34 is pulled
and/or rotated so as to create a releasible or temporary connection
between the head 34 and the plaque engaged by the blades 36, as
shown in FIG. 3. This grasping, grabbing, clamping, binding or like
phenomenon causes the connected plaque to move as the instrument
head 34 is moved by manipulation of the external control. Thus, the
head 34 can be moved back and forth and/or can be rotated in one or
the other or both directions so as to radially and/or
circumferentially sever or shear the plaque from itself, as
illustrated at site 42 in FIG. 2. The instrument 20 and its head 34
are retracted in a generally longitudinal or axial direction,
either alone or in conjunction with back and forth movement as well
as selected rotational movement in one or the other, or both
directions. This causes the plaque to be sheared, peeled, or be
severed from the internal surface 44 of the internal wall 46 of the
artery 22, which defines the boundary between the arterial wall and
the engaged plaque. It is to be appreciated that as arterial
disease progresses, this boundary between the diseased and
undiseased arterial wall may be located within the interior layer
46, or between layers 46 and 52, or within layer 52, but does not
generally invade layer 50. The severed unitary plaque segment 26'
is retrieved together with the connected head 34 and removed
through the man-made opening in the artery and when removed and
disconnected from the head has a won-like appearance as shown in
FIG. 10. Plaque segment 26' might be called an endarterectomy plug.
Medically speaking, it is by definition an endarterectomy plug,
although the endarterectomy has been achieved by novel,
nonconventional techniques.
In medical tens, the artery 22 comprises an outside layer 50 known
as the tunica adventitia, a central, radially larger intermediate
layer 52, known as the tunica media, and the previously mentioned
interior layer or wall 46, known as the tunica intima endothelium.
The plaque 26 is typically referred to as atherosclerotic plaque,
which in advanced stages of disease such as are typically treated,
partially or wholly, engulfs the tunica media.
The present invention, as stated earlier, does not contemplate
cutting, grinding, or fragmenting pieces of plaque 26 from the
atheroma, but rather is directed to grasping, gripping, clamping,
or otherwise releasibly connecting the instrument head to the
plaque for intact removal of a segment of plaque and in certain
embodiments, including the embodiments disclosed herein,
contemplates simultaneously creating a tapered interface. The
creation of the tapered interface is advantageous in that, after
the treatment when flow is restored, a tapered interface in the
upstream direction will help prevent the creation of undesirable
flaps of disease being lifted from the vessel wall, as the flow
over the tapered disease will press the disease more firmly into
the vessel wall, and also reduce flow turbulence at the
interface.
Reference is now made to the instrument illustrated in FIGS. 4-6,
which is generally designated 20'. The instrument 20' is connected
and controlled as is the above-described instrument 20. Only
differences between instrument 20 and instrument 20' need
description here. The numerals used in FIGS. 4-6 which are
identical to numerals used in FIGS. 1-3 identify identical or
substantially identical parts. The instrument 20' differs from the
instrument 20 primarily in the configuration of connector head 34'.
Head 34' comprises a plurality of spaced, somewhat
longitudinally-extending blades 36' anchored, respectively, at the
proximal ends 38 thereof to the distal portion of the tube 30 and
non-rotatably joined to the tip 40. Each blade 36' comprises a
proximally-directed barb 37'. While each barb 37' is illustrated as
being disposed at a slight acute angle in respect to the
longitudinal axis of the artery 22, any suitable barb orientation
may be used.
When the tube 32 is retracted by the external control in respect to
tube 30, tip 40 is displaced toward proximal portion 38, causing
the blades 36' of the head or connector 34' to flex radially
outwardly. Withdrawal (retraction) and/or rotation of the head 34'
causes the blades 36' to bite into, but not sever away pieces of
the plaque 26. Generally longitudinal retraction of the instrument
20', including connecting head 34' with the plaque 26 bindingly
connected between the blades 36', accommodates severing or shearing
of the plaque at radially-directed site 42 thereby separating
plaque segment 26' from residual arterial plaque 26. This severing
or shearing can create a tapered or beveled interface. The
retraction of the instrument 20' may be accompanied by to and fro
longitudinal movement of the head 34', retraction only and/or
rotation in one or the other or both directions sufficient to
sever, shear, or peel the plaque segment 26' from the annular
interface 44 of the inner layer 46 of the artery 22, or at whatever
depth the diseased/non-diseased interface has progressed, as
described earlier.
The severed plaque segment 26' is retrieved and removed from the
artery through a man-made opening therein as the instrument 20' is
removed, the head 34' remaining releasibly connected to the plaque
segment 26' during retrieval and removal.
Reference is now made to the unitary plaque segment removal
instrument, generally designated 20", illustrated in FIGS. 7-9. To
the extent parts of instrument 20" illustrated in FIGS. 7-9 are
identical or substantially identical to parts previously described
in connection with FIGS. 1-3, identical numerals are used and no
further description thereof is necessary.
Tube 30 and distal portion 38 thereof do not form a part of the
embodiment illustrated in FIGS. 7-9. Instrument head 34" is
non-rotatably secured at the distal end of tube 32 and is inserted
into the desired location along guidewire 28. The instrument head
34" is illustrated as maintaining a constant transverse dimensional
configuration.
Head 34" comprises a plurality of curvilinear blades 36", each of
which is illustrated as carrying a pair of curved hooks 39, which
engage the plaque when rotated so as to pierce portions thereof
without severing pieces of plaque therefrom. Thereafter, by
displacing the head 34" to and fro, or by retracting alone and/or
rotationally as desired and by primarily retracting the head 34"
along the length of the artery 22, plaque segment 26' is loosened,
severed, retrieved, and removed from the artery through a man-made
opening therein.
Reference is now made to FIG. 12, which illustrates the same
apparatus as shown in FIGS. 1-3, illustrating placement of the
instrument head 34 into the artery between the plaque 26 and the
arterial wall surface or cleavage interface of weakness 44 and
advanced along the arterial surface 44 to the desired plaque
connection site without prior use of an interface separation
tool.
The invention may be embodied in other specific forms without
departing from the spirit of essential characteristics thereof. The
present embodiments therefore to be considered in all respects as
illustrative and are not restrictive, the scope of the invention
being indicated by the appended claims rather than by the foregoing
description, and all changes which come within the meaning and
range of equivalency of the claims are therefore intended to be
embraced therein.
* * * * *